While scientists have known for a while that flavonoid-rich foods could help bolster our immune systems, they weren’t really sure why. Now, a new study in the journalSciencehas found they might work with microbes in your gut to reduce the damage from the flu.

“It’s not only having a diet rich in flavonoids, our results show you also need the right microbes in the intestine to use those flavonoids to control the immune response,” said the study’s senior author, Dr Thaddeus Stappenbeck.

In this study, researchers screened human gut microbes to find one that metabolised flavonoids. The authors identified one calledClostridium orbiscindens, which they thought might do the trick.

This interaction between the microbe and the flavonoids produced a metabolite called DAT. When this DAT was given to mice infected with the flu, the mice experienced less lung damage than mice not treated with DAT.

Here’s the interesting part: both groups of mice had the same level of influenza infection – it was just the lungs of the treated mice were way less damaged by it.

“The infections were basically the same,” Stappenbeck said. “The microbes and DAT didn’t prevent the flu infection itself; the mice still had the virus. But the DAT kept the immune system from harming the lung tissue.”

This is important, as sometimes the flu is impossible to avoid – even if you’ve had a vaccine. So this method doesn’t aim to stop the virus, it just treats your body’s response to the virus. This could be a critical discovery, as while the word 'flu' is often misused – it’s actually a serious viral infection of the upper respiratory tract – not just a few sniffles.

While further research is underway, the authors suggest drinking black tea and flavonoid-rich food to boost your immune system in the meantime. Oh, and a cheeky glass of red wouldn’t hurt, either.